In the field of data processing, there are always requirements for and efforts made to increase the speed of operation in order to provide a larger thruput of data. It is, of course, well-known that the standard typewriter keyboard or the QWERTY arrangement, so named for the first six letters of the upper alphabetic key row, has been in use for over 100 years. A new keyboard arrangement is the MALTRON arrangement which makes keys easier to operate by tilting the keyboard toward normal hand and body positions. The MALTRON arrangement also saves time and motion by dividing keys into more efficient groups in that ninety percent of the most often used letters are on the home row, where the operator's fingertips are normally placed in touch typing, as contrasted with fifty percent of the most often used letters on the home row in the QWERTY arrangement.
Another type keyboard uses the conventional ten key arrangement wherein data entry consists of serially depressing one or more numeric data keys followed by a non-numeric data entry key. The numeric keys are constituents of a numeric data field and the field is entered via a subsequent entry key depression. It is seen that because the entry key always follows the last numeric key of the numeric data field, its serial location or the location of the entry key in the keying sequence provides inherently redundant information to the keyboard processor. If the last numeric key and the entry key were depressed simultaneously rather than serially, the same information would be provided. In addition, considerable keying time would be saved since the serial time required to enter the last numeric keystroke of the numeric data field would be eliminated. It is also known that an analysis of current data entry keyboard decoding logic indicated that redundant information is present when an entry key is depressed serially after entry of every numeric data field.
In the area of dual keypad arrangements wherein the right hand makes the numeric entry and the left hand makes the function entry, there are indications of problems with current keyboard operations. In one aspect of the dual keypad arrangement, the keyboard logic rejects successive key entries occurring within 30 milliseconds of each other and provides a warning to the operator of this condition. This logic prevents many potential operator errors and appears to work successfully with successive numeric or right hand entries. However, when the left hand depresses the enter key immediately after the numeric entry, it frequently occurs within the 30 millisecond error window when no operator error has actually occurred. In other words, successive key strokes from different hands appear to occur faster than successive key strokes from the same hand. Of course, it is a known fact that operators have no problem consistently depressing the last digit of an amount and the entry key simultaneously. If this condition were allowed by the keyboard logic in dealing with an average bank document containing approximately 4.5 digits, it would reduce the entry time of each amount by an average of about 150 milliseconds or the time required for a single serial key stroke.
Representative documentation in chord entry keyboards and chord entry keying of data includes IBM Technical Disclosure Bulletin Vol. 21, No. 7, December, 1978, entitled "Chord Keyboard With Case Lock and Chord Definition Features" by R. J. Bamford et al., wherein dimples in the finger keys and troughs in the thumb keys enhance the usability of the keyboard.
IBM Technical Disclosure Bulletin Vol. 21, No. 9, February 1979, entitled "Keyboard Device for Upper and Lower Case Keying Without Shifting" by D. Bantz et al., discloses a pressure-sensitive method and a time-delay method of detection of key strokes as a more convenient way of keying upper case characters.
IBM Technical Disclosure Bulletin Vol. 22, No. 12, May 1980, entitled "Typamatic Feature for Chord Keyboard" by F. C. Bequaert, discloses a feature which permits a user to produce a given character (or sequence of characters) repetitively without having to strike a key (or keys) repeatedly.
U.S. Pat. No. 3,270,853, issued to H. Gerjets et al. on Sept. 6, 1966, shows keyboard apparatus having means to control actuation of circuit impulses for preventing simultaneous actuation of two or more keys.
U.S. Pat. No. 3,675,239, issued to H. T. Ackerman et al. on July 4, 1972, shows an unlimited roll keyboard circuit indicating that a certain key within the keyboard was depressed both during the first strobe pulse and also during the second strobe pulse.
U.S. Pat. No. 3,717,871, issued to I. Hatano et al. on Feb. 20, 1973, discloses a keyboard input device wherein means is provided for obtaining an inhibit signal to prevent the entry of unnecessary input signals resulting from keys operated in such a way that during depression of one key another key is singly or repeatedly operated.
U.S. Pat. No. 3,750,160, issued to J. M. Elzinga on July 31, 1973, discloses a keyboard with a rollover feature wherein two or more keys may be jointly depressed.
U.S. Pat. No. 4,042,777, issued to F. C. Bequaert et al. on Aug. 16, 1977, discloses a one-handed chord keyboard having a finger section and a thumb section for typing of chords formed by simultaneous pressing of one or more keys on the keyboard and control means including switch combinations for each chord on the row of keys.
And, U.S. Pat. No. 4,121,048, issued to R. N. Dev Choudhury on Oct. 17, 1978, discloses a multiple shift electronic keyboard with a shift key utilized to indicate the start of a shift operation and the end of the operation.